Does electricity weigh anything?
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On a newtonian level electricity doesn't have mass...if you think of it as energy...
When you "charge" a battery, you are essentially forcing a chemical (albeit temporary) change. Some chemical reactions will of course evolve or use or otherwise effect mass, but this does not mean electricity "weighs anything".
When you "charge" a battery, you are essentially forcing a chemical (albeit temporary) change. Some chemical reactions will of course evolve or use or otherwise effect mass, but this does not mean electricity "weighs anything".
My understanding is that, if Einstein's famous equation E = M*C*C is true, then the mass of a battery is greater when it is charged than when dead, but this mass difference is infinitesimally small, so much so as to be unmeasurable. Likewise an alarm clock, not electric, for example, but the windup kind, has more mass wound up than wound down. Not saying this is true (though it may be and likely is), but I read it somewhere.
[ February 15, 2004, 12:08 AM: Message edited by: TallPaul ]
[ February 15, 2004, 12:08 AM: Message edited by: TallPaul ]
I was in a meeting at work a little while ago, and was talking to the electrical engineers about electricity flowing in circuits.
They all agree that yes, electrons have mass, and that yes, the speed of light is very fast.
When I asked why they didn't have to put thrust nlocks on the corners when they ran a cable around a building, while I had to with water, whih is going 100,000,000 times slower, they just sat looking stunned.
They all agree that yes, electrons have mass, and that yes, the speed of light is very fast.
When I asked why they didn't have to put thrust nlocks on the corners when they ran a cable around a building, while I had to with water, whih is going 100,000,000 times slower, they just sat looking stunned.
Hi,
Just wanted to give my 2 cents.
E=mc2 as I understand relates to the max energy you can possibly obtain from a certain mass as well as telling us that it would be impossible to accelerate anything of any mass to the speed of light. As speed approaches c, energy goes to infinity.
Average speed of electron in conducting (copper) wire is about 10^6 m/s. At the same time the drift speed of the same electron is about 10^-4 m/s. So the actual speed of electricity is not that great (10^-4 m/s if you haven't got it yet).
Pablo is right. Electric company sells energy, not mass. Electrons are passing thorough the wires they have mass, but they do not go away. Just slow down a bit - therefore mass stays. Energy (electric) is converted to other forms of energy.
Energy = Power * Time
Power = Current * Voltage = Voltage^2 / resistance … and etc.
Electricity does not have a mass. Unless there is someone here who could go into quantum physics and prove/explain that it might not totally be true in some cases. Even if it would be possible to show it (I highly doubt it), conclusion could only be applied to a handful of situations beyond any practical applications.
Regards,
Just wanted to give my 2 cents.
E=mc2 as I understand relates to the max energy you can possibly obtain from a certain mass as well as telling us that it would be impossible to accelerate anything of any mass to the speed of light. As speed approaches c, energy goes to infinity.
Average speed of electron in conducting (copper) wire is about 10^6 m/s. At the same time the drift speed of the same electron is about 10^-4 m/s. So the actual speed of electricity is not that great (10^-4 m/s if you haven't got it yet).
Pablo is right. Electric company sells energy, not mass. Electrons are passing thorough the wires they have mass, but they do not go away. Just slow down a bit - therefore mass stays. Energy (electric) is converted to other forms of energy.
Energy = Power * Time
Power = Current * Voltage = Voltage^2 / resistance … and etc.
Electricity does not have a mass. Unless there is someone here who could go into quantum physics and prove/explain that it might not totally be true in some cases. Even if it would be possible to show it (I highly doubt it), conclusion could only be applied to a handful of situations beyond any practical applications.
Regards,
Titanium, the analogy I used was likening it to a a pipe full of billiard balls. THe blass were moving quite slowly, but as soon as one is pushed in, "it" (or another one just like it) pops out the other end almost instantaneously.
If we sold electricity on the number of electrons, our beancounters would be specifying quotes down to the nearest (1/6)^-23 amps give or take.
If we sold electricity on the number of electrons, our beancounters would be specifying quotes down to the nearest (1/6)^-23 amps give or take.
Electricity is the net movement of electrons that would otherwise have no net movement. So, in that context, "electricity" in a wire adds no mass compared to the same wire without electricity, and therefore electricity has no "weight". A static charge of electricity could have imperceptable positive or negative weight, depending on whether the charge was positive or negative.
A battery's weight does not change between a charged or discharged state, forgetting, of course, any gasses that might be given off in the charging or discharge process. In a lead acid battery, the specific gravity, and therefore the weight, of the acid goes up as the battery is charged, but this reflects materials that have been taken out of the lead plates and into the acid.
A battery's weight does not change between a charged or discharged state, forgetting, of course, any gasses that might be given off in the charging or discharge process. In a lead acid battery, the specific gravity, and therefore the weight, of the acid goes up as the battery is charged, but this reflects materials that have been taken out of the lead plates and into the acid.
Does moving water in a garden hose weigh more than standing water in a garden hose?
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Again ..you guys are way outta my league here ..but..
Comments??
What about purely inductive circuits? They, at least for the first 5 time constants have current flow "in" ..but no current flow "out". This also must lead some of you to plug in "power factors". Some have described this as "aerated water".
Comments??
I could be wrong, but I thought there has to be an equal current flow out for there to be current flow in. Voltage does lead current on an inductive circuit though: application of voltage results in a current that builds non-instantaneously (it lags voltage).
I suspect the water is acting enmass, but in the electrical cable the electrons are all running their own little paths, thereby breaking up any combined inertial effect, probably because it is alternating current. I wonder if say 10,000 volts of direct current suddenly entered an electrical cable whether it would cause the cable to jerk and jump.
If the mass of water in the hose is the same whether it is moving or not, the weight is the same. The weight of water in a moving hose may be a little less if the water is moving so quickly that it causes turbulence and cavitation within the hose, so that some of the volume is gas voids, and not 100% liquid water.
Weight and mass are two different quantities. Weight would be a function of the velocity of the water and radius of curvature of the hose as well as orientation of the hose relative to the Earth's gravitational field.
Mass for all practical purposes would not change at sub-relativistic velocities.
My simple understanding from HS physics is that weight is the measurement of the gravitational pull on mass?? Now if moving water through a hose experiences resistance does the water compress (slightly of course) due to this resistance and therefore gets a higher mass and therefore more weight? Would this apply to current flow in a wire that also sees resistance, compression of the electrons, higher mass, more weight????
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Yes, ELI the ICE man (Voltage leads current by 90 degrees in an inductive circuit - current leads voltage in a capacitive circuit by 90 degrees).
But since full applied voltage (for at least 1 of the first 5 time constants) is read across the inductor ..it's an "apparent" open ..no current flow can be taking place. The current is "held up" by the EMF created by the inductor ...until the magnetic field is fully expanded.
So ..I guess the current does "stop" per se ..but at least for a moment (at least 1 of the first 5 time constants) there is flow into the conductor ..but no flow out ..the inductor being a "virtual open" ..an accordian that reaches saturation and then turns into a straight piece of wire.
What does this have to do with the "weight" of electrons??
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